The Complexity of Urban Drainage Projects in Megacities: The Case of the Agua Preta and Sumare Catchments of the City of Sao Paulo, Brazil

This paper presents the urban drainage study of two small urban catchments in the city of Sao Paulo, Brazil. Sao Paulo is a megacity with more than 11 million inhabitants, with enormous social, technical, economic, and environmental problems. Among them is the flooding of several areas during the rainy season. It can be observed that the dense soil occupation, together with the above mentioned problems, shows how diverse and complex is the urban water issue. It is fundamental in studies like this to assess and analyze the causes of floods. Another key issue is how the impacts of urbanization are related to the various hydrological processes, which are even more sensitive in tropical and subtropical cities. The main question to be discussed is how to use various techniques of sustainable urban drainage in densely occupied areas in a city like Sao Paulo. The case study presents two catchments, located in the central region of the city, constituted by extremely sensitive areas, occupied for housing, mobility, services, and other city demands. Proposals for flood control intervention are also presented.